gen1 = (ord(c) for c in 'CS 340!')
def allprimes():
    """This uses the ancient algorithm known as the Sieve of Eratosthenes"""
    yield 2
    found = [2]
    next = 3
    while True:
        cap = next**0.5
        for p in found:
            if p > cap:
                yield next
                found.append(next)
                break
            if (next % p) == 0: break
        next += 2
gen2 = allprimes()

print(gen1, gen2)
print(gen1.__next__(),gen2.__next__())
print(gen1.__next__(),gen2.__next__())

for codepoint in gen1:
    print(codepoint,'came from',repr(chr(codepoint)))
for p in gen2:
    print(p,'is prime')